Furnace for heating fluids



Feb. 15, 1944.

J. H. RICKERMAN Filed A ril 10, 1941 5 Sheets-Sheet l lNVENTOR 1 BY% aATTORNEY Feb. 15, 1944.

J. H. RICKERMAN 5 Sheets-Sheet 2 Filed April 10. 1941 JOHN 11mm mam/Wm.

lNVENTOR FIG. 2 l

ATTORNEY Feb. 15, 1944.

J. H. RICK'EJRMAN 7 Filed April 10, 1941 5 Sheets-Sheet 5 INVENTOR avg;I

ATTORNEY Feb. 15, 1944. J, H .RICKERMAN FURNACE FOR HEATING FLUIDS 5Sheets-Sheet 4 Filed April 10, 1941 FIG-4 F 175,1944- J. H. RICKQERMAN 72,342,011

FURNACE FCSR HEATING FLUIDS Filed April 10, 1941 5 Sheets-Sheet 5 JOHNHERMHN RIC/(ERMHM INVENTOR ATTORNEY be released within Patented M15,1944 UNITED STATES PATENT OFFICE FURNACE fi rmo FLUIDS John Her manRlckerm'an,

River Edge, N. J... as?

signor to The M. W. Kellogg Company, Jersey City, N. J., a corporatio nof Delaware ApplicationtApi-il 10, 1941, Serial No. 387,199

7 Claims. (Cl. 122-356) 1 This invention relates to the heating offluids and to apparatus therefonand is particularly concerned with theheating 0 hydrocarbonfluids by; passage thereof through v connectedtubes located in a combustion chamber. I

In'the designof oil heating furnaces of the latter type it is constantlynecessary to reconcile as far as, possible three essential requirementswhich are in conflict with each other. The cost of a furnace is'to agreat extent dependent upon its dimensions, each square foot of wall androof area requiring the expenditure of a certain amount of money for therefractory or other material of which it is'constructedand for the steelnecessary for its support. The first requirement is therefore that afurnace be made as small as possible in order to reduce construction'costm Present methods of liberating ,heat by combustion being what theyare, however, there is a limit to the amount of heat which can a givencubicvolume without the development of excessively high temperatures,which would hasten the disintegration of refractory and metal partslocated therein and produce undesirable effects upon the fluid to beheated. The second, requirement, therefore, is

plurality of interthat the combustion chamber of a furnace be madesufliciently large to avoid destructively .high temperatures locallythereof. To a certain extent the latter two requirements may be rec;-

struction wherein the three requirements enu-- merated will .bereconciled to a superiorde'gree, in order that hydrocarbon ofls may moreefllciently and at lower cost.-

types by its sloping side walls and its approximately triangularvertical cross section. These features give the structures. shape whichrebe heated edge upward. It is contemplated by the invention to positionparallel interconnected tubularconduits for fluids to be heatedhorizontallywith- .in thecombustion chamber defined by the wedgeshapedstructure, adjacent and substantially parallel to the sloping wallsthereof. The invention further contemplates positioning additional fluidheating tubes within the combustion chamber adjac'ent the upper narrowportion thereof, so as to make upa tube bundle occupyingthespace betweenthe converging side walls. Additional features contemplated by thispreferred embodiment of the invention include a multiplicity of separateburners located in a horizontal plane parallel to anct approximatelycoincident with the bottom of the combustion chamber. These burners arearranged inrows paralleling the fluid heating tubes and are providedwith means for controlling the amounts of fuel supplied to the b ers inthe individual rows; Products of combustion travel upwardly from thefloor of th combustion space,

and after .passing between and around the tube bundle in the convergingportion emerge from the top of the combustion chamber into a suitableconduit leading to a stack. c

The advantages of the furnace structure herein disclosed are many innumber. Support for the refractory walls of the combustion chamber andfor the tubes may be provided with exterior structural members havingthe so-called A-shape used in the bents of bridges and trestles which,as

is well known, is superior from the standpoint of strength and rigidity.Aside from the purely load-supporting advantages of the Iwedge-shapeconstruction, highly advantageous tube arrangements and methods offiring are thereby made possible. In prior known furnaces of more orless rectangular cross-section, no matter where the burnersarelocatedthere is great irregularity and asymmetry in thedistances ofdifierent tubes from the burners. In such furnaces the differingdistances of the tubes from the burners cannot be compensated for byindividual adjustment of The furnace structure of my invention, in its isembles that of a truncated or blunt wedge, resting upon its back withits truncated narrower the burners. It is impossible to liberate heat inthe corners of a rectangular furnace if all the tubes are tobe heated ata high and uniform rate, and such dead spaces reduce, the mean rate ofheat liberation for the furnace as a whole. In my improved furnace,however, there is a regular divergence between rows of tubes and rows ofburners.- Since the burner rows are individually controllable, I mayregulate the amounts of fuel supplied to and lengths of the flamesissuing from the burners in proportion to their distances from thetubes, and thereby liberate a maximum amount of heat'in all parts of thecombustion chamber, without great variation in the rate of heating fromtube to tube.

Other objects and advantages of the invention will appear during thecourse of the more de-' tailed description now to be given withreference Fig. 3 is an isometric view of still another type of structurealternate to Figs. 1 and 2; I 1

Fig. 4 may be considered a sectional end elevation of any one of thethree furnaces shown in the first three figures showing one optionaltubearrangement and the locationof burnerswith respect thereto; 1

Fig. 5 is an isometric phantom view in detail of one type of burnerassembly suitable for use in connection with the invention; 1 I

Fig. 6 is a purely diagrammatic representation of an alternate tubearrangement capable of being embodied in .the structures shown in thepreceding drawings, and

Figs. '7 and 8 are further diagrammatic tube arrangements exhibitingvarious features within the scope of the invention.

ucts at the top of the combustion chamber is unobstructed by anystructural members such as I02 and 202 as in Figs. 1 and 2. The weightof the refractory walls 305 and 309 is transmitted by the stays 30I andbraces 303 to girders 304 extending along the tops of the inclinedwalls.

The girders 304 in turn transmit the load to the main top cross member302 at the extreme ends of the frame. An elongated stack breeching 30!collects products of combustion along the entire upper portion of thecombustion chamber and conveys them to duct 308 which may lead to astack or other apparatus such as an air preheater or economizer.

It will be understood that the furnace structure of my invention is notlimited to the particular proportions and arrangements shown in Figs. 1to 3. In general I mayemploy wedge- In Fig. 1 six I-beams IOI of whichonly four are by smaller beams I03 intermediate their length.

The tops of beams IOI are additionally braced by members I04 so that theassemblage consistingof members IM to I04 forms a supporting frame forrefractory walls I05 and I09 enclosing a combustion chamber. A headerbox I06 has a counterpart concealed from view on the the opposite end ofthe structure and covers the connections between the ends of tubeslocated along the sloping walls and adjacent the roof of the combustionchamber. Stack breechings I01 communicate with the interior of the com-.bustion chamber and are adapted to convey products of combustiontherefrom into the stacks I08. It will be observed that the structureshown in Fig. 1 employs relatively short roof supporting members I02 byreason of its converging side walls. Their short length decreases theirweight and cost relative to the roof. members used in prior knownfurnaces having broad flat roofs.

In Fig. 2 the method of framing shown is identical to that of Fig. 1comprising inclined members 20I, top cross members 202, braces 203 and204, refractory walls 205 and 209 and header boxes 206, but embodies asingle bifurcated stack breeching 201 which surrounds the middle one ofthe three top cross members 202 while providing an air tunnel thereforto permit air cooling thereof. The construction of Fig. 2 may beemployed when it is desired that only the one stack 208 be used.

Fig. 3 embodies a more extensive departure from the structures alreadydescribed but still partakes of the advantages of the invention. In thisstructure the exit area for combustion prodshape structures of varyinglengths and heights and thereby provide furnaces of any desiredcapacity. When long furnaces are used the stack arrangement of Fig. 1will be preferable, while with the shorter lengths the breechings ofFigs. 2 and 3 may suitably be employed.

In Fig. 4, which, as previously mentioned, represents a sectional endelevation of any one of the structures shown in Figs. 1 to 3, theinclined beams 40I support refractory walls 0 and rest upon suitablefootings 4II. Tubes 2 are arranged in parallel rOWs longitudinally ofwalls M0 and hence appear in Fig. 4 as circles. Burn,- ers 4l3 arearranged in rows, only the ends of which are visible, and. areindividually controllable row by row as will be hereinafter more fullydescribed, so that they may receive fuel at different rates and-produceflames of graduated height as shown. Because of the locus of tubes 4 I2relative to the burners, they will receive heat predominantly byradiation and hence may be referred. to as radiant tubes, in accordancewith the usual furnace nomenclature. Tubes 4 are situated'approximatelyat the apex of the section and are nested closely together so that hotproducts of combustion liberated by burners 412 must pass at relativelyhigh velocity between and around them. They will receive heatpredominantly by convection and are properly described as convectiontubes.

The advantages of my improved furnace structure in enabling a maximumrate of heat liberation throughout a combustion chamber will be readilyapparent from a view of Fig. 4. The centrally located rows of burnersbeing farthest from heat absorbing surfaces may feasibly produce flamesof greater intensity so as to effect a high rate of heat liberation inthose regions of the combustion chamber not occupied by nor lyingadjacent to any parts subject to overheating. At the same time the rowsof burners at the sides of the combustion chamber may be fired lessvigorously so as to protect the steel and refractory parts in closeproximity thereto while utilizing the available volume for theliberation of appreciable quantities of heat. This arrangementfacilitates systematic heat distribution to all the tubes of the slopingradiant banks. All the combustion products converge on the convectiontubes 4 and acquire a high velocity by reason of the constricted upwardpassageway so that a maximum amount of heat can be recovered therefrombefore release into the stack or stacks. In the particular tubearrangement shown in Fig. 4 fluid to be heated may be introduced intothe interconnected rows of tubes in two parallel streams by way 'ofinlets H9 and the the apex of the cut that t is tube arrangement insuresthat the two. strea' will be heated identically-as the two streamstraverse equal numbers of substantially equally furnace.

Fig. illustrates one type of burner arrange- .ment suitable for use inconnection with the furnace of Fig. 4. 5l5 represents a slab orfoundation of concrete or refractory of alength equal to that of acombustionchamber. This base is recessed or slotted as shown to providesupport bustible material released by. any one of the pipes 5I3 runninglongitudinally heated tubes before leaving the The burner pipes areprovided with withdrawn from outletsll8. It will be apparburner pipesmay be individually controlled by" means of the respective valves. Airfor the combustion in controlled amount is supplied either by natural,forced, or induced draft through air ducts 5 I 1 extendingperpendicularly of the burner pipes" through the foundation slab iii andopeninginto the recesses in which the burner pipes lie.

gIt'is to be understood that the burner arrangement shown in Fig. 5 ispurely exemplary as numerous other constructions for producing inand beadapted for use in connection with in e tion. l

In Fig. 6 I have shown an alternate tube arrangement for producingidentical heating. of two parallel fluid streams wherein a greaternumber of tubes are .used in the convection bank. The .radiant tubes BIOare disposed as in Fig. 4 but the'convection tubes 6' fill in the apexof the combustion chamber relatively completely. The arrangement in Fig.6 in comparison with that of Fig. 4 illustrates how the relative'sizesof the radiant and convection sections. may be varied within a givenfurnace volume.

Allthe usual methods of adjusting the rate of heating of a fluid streamor streams may be available of in connection with my improved structureas, for example, the use of double rows of tubes in a radiant bank. mentis shown by Fig. 7 as it might be used. to

heat a single'fiuid stream. .The radiant tubes 1 ll] are conventionallyarranged but the convection section embodies a feature of the. inventionwhich may be-of particular value when a high efficiency is desired in arelatively small convection section. Asindicated by the figure,convection tubes 1| 4 have been arranged in a relatively narrow bundlecentrally located within structure. What would normally be free space oneither side of the bundle is filled in with refractory so'that productsof comv bustion are required to traverse a relatively constricted paththrough the convection tube bundle. By this means a higher velocity andimproved heat transfer is afforded. Moreover by stepping in therefractory filler as shown and making the tube bundle progressivelynarrower with height. the combustion gases are given anincreasingvelocity concurrent with lowering of their temperature by heat transfer.In this manner the tendency for heat transfer to decrease withtemperature may be counteracted and heating made more uniform throughoutthe convection bank.

Fig. 8 illustrates still another modification of the tube arrangementcontemplated by the in- Such an arrangelike.

. 30 divid ally controllable rows of flames are known to the base. Iradiation between the two sides of the furnace. Convectiontubes 8 arearranged compactly in 'velo city and 8") are arranged in a single rowalong the entire height of the left handwall of the furnace while on theright hand wall they are arranged in a not extend all the way A bridgewall 820 minimizes crossdouble row which does a manner alternate to thatof Fig. 7 between projecting refractory corbels to provide highercreased heat transfer for the products of combustion passingtherethrough.

'The improved furnace construction of my invention is capable ofreceiving a variety of mechanical expressions and may inconporate agreater number of separate fluid heating circuits in any one furnacethan have been indicated in the drawings. invention is of particularadvantage in connection with hydrocarbon conversions effected atelevated temperatures such as thermal and catalyticcracking,.polymerization, reforming and the It may advantageously beused to heat hydrocarbon oils prior to distillation thereof andmay'incorporate in a common combustion chamber both oil heating andsteam generating coils. It is to be understood furthermore that I am notlimited by any of the examples given herein for purposes ofillustration.

I claim:

1. In a furnace for heating fluids, the combination which comprises acombustion chamber having a fiobr, a furnace wall bounding said chamberand inclined inwardly with respect thereto, a

" pluralit'yof fluid-conducting conduits disposed two adjacent saidwall, a plurality of burners located in said fioorand adapted to projectproducts of combustion upwardly directly therefrom toward said wall, andmeans for controlling the firing of erally toward theconvergence of saidwalls, and

means for controlling the firing of said burners to effect lessintensive firing of said burners closest to said sloping walls thanthose farthest from said sloping walls.

4. A furnace as in claim 3 wherein saidedges are the lower edges of saidwalls and said burners are directed vertically upward.

5. A furnace for heating fiuids comprising a furnace floor, two sidewalls rising upwardly and inwardly toward each other at acute anglesfrom opposite sides of said floor, two. end walls rising from the othertwo opposite sides of said our, said four walls and said floor enclosinga combustion chamber having a relatively broad base and a relativelynarrow opening for the escape of combustion products between theuppermost edges of said inclined side walls, corbels projecting inwardlyfrom said side walls just below said opening so as to enclose betweenthem a narrowed passage forcombustion products ap- While not limitedthereto, my

proaching said opening, a plurality of interconnected conduits forfluids disposed adjacent and parallel to said side walls, a plurality oflike conduits relatively compactly disposed within said passage, aplurality of burners adapted to produce hot products of combustion forsaidcombustion chamber and means for controlling the firing of saidburners to effect less intensive firing of said burners closet to saidrising walls than those r refractory-walls bounding two sides of saidchamher and having a relatively narrow opening between their uppermostedges for the escape of combustion gases, a plurality offluid-conducting conduits disposed adjacent said refractory walls.

and means for controlling the firing of said burners to eifect lessintensive firing thereof closest to said sloping walls than thosefarthest from said sloping walls.

7. A furnace for heating fluids which comprises a combustion chamberiimited in one direction by a burner setting, a plurality ofinwardlydirected burners in said setting, the cross-sectional area ofsaid chamber in a plane coincident with said setting being greater thanin any I parallel planeappreciably distant from the plane of saidsetting, sloping refractory walls bounding two sides of said chamber inother directions and w provided with an opening opposite said burnersetting for the escape of combustion products, a

plurality of fluid-conducting conduits disposed v adjacent said walls,and means for controlling the firing of said burners to effect lessintensive firing thereof closest to said sloping walls than 20- thosefarthest from said sloping walls.

J. HERMAN RICKERMAN.

